Copper fluoroborate-aromatic complexes and preparation thereof



Sept. 20, 1960 D. A. 'MOCAULAY COPPER FLUOROBORATE-AROMATIC COMPLEXES AND PREPARATION THEREOF Filed Feb. 6, 1956 0 HQ m m i m M 9 V NT m A M S Q v Q. Q Q m V. B & QEE G w ATTORNEY 2,953,589 COPPER FLUOROBORATE-AROMATIC COM- PLEXES AND PREPARATION THEREOF David A. McCaulay, Chicago,

Oil Company, Chicago, 111., a

Filed Feb. '6, 1956, Ser. No. 563,477 22 Claims. c1. 260--438) 111., assignor to Standard corporation of Indiana This invention is concerned with complexes of copper fluoroborate and aromatic hydrocarbons. Also, it is concerned with recovery of aromatic hydrocarbons from admixture with non-aromatic hydrocarbons utilizing copper fluoroborate or a copper fluoroborate-aromatic hydrocarbon complex.

It has been discovered that the copper fiuoroborates form complexes with aromatic hydrocarbons, which complexes are stable at atmospheric temperature and pressure, that is, temperatures at least as'high as 60 C. at pressures on the order of 760 mm. Hg. These copper lluoroborates are cuprous fluoroborate, i.e., CuBF and 'cupric fluoroborate, i.e., Cu(BF The copper fluoroborates form complexes Which contain either one or two moles of the particular aromatic hydrocarbon per mole of copper fluoroborate. The empirical formula of the complex may be set out as Cu(BF (Ar) where x is an integer not exceeding 2, y is an integer not exceeding 2, and Ar is the aromatic hydrocarbon. In other words, x is either 1 or 2, and y is either 1 or 2.

The complex containing 1 mole of copper fluoroborate and 2 moles of aromatic hydrocarbon is readily changed to a complex containing 1 mole of copper fluoroborate and 1 mole of aromatic hydrocarbon by heating the -Cu(BF.,) (Ar) complex until one mole of aromatic hydrocarbon has been decomplexed. The temperature at which the Ar complex must be heated is dependent upon the pressure maintained on the decomplexing zone. In general, the higher the pressure the higher the temperature needed. To illustrate, the complex CuBF .2 (benzene) can be converted to the CuBF .1 (benzene) complex by heating for, on the order of one hour, the '2 (benzene) complex at 100 C. and atmospheric pres- :sure.

The aromatic hydrocarbon component of the complex can be recovered completely by heating the complex at sufficiently high temperature to decompose the complex to copper fluoride, BF and aromatic hydrocarbon. It does not appear to be possibleto recover the second mole- :cule of aromatic hydrocarbon Without also decomposing the copper fluoroborate itself. The .complex is completely destroyed by prolonged heating at moderate temperatures, under vacuum, or high temperatures and ordinary pressures. Forexample, heating for several hours :at 100 C. at mm. Hg or at atmosphericpressureat temperature on the order of 150 C.200 C.

The physical characteristics of the complex are deg'pendent upon the aromatic hydrocarbon and also upon "the number of molecules of aromatic hydrocarbon present in the complex. For example, CuBF .2 (benzene) is a yellowish-white liquid at about 25 C. and atmospheric "pressure. CuBF .2 (m-xylene) is a solid forming white needle-like crystalsat ambient temperature and. pressure. This complex issensitive to atmospheric humidity and when exposed tohumid atmosphere, apinkish color ap .peared on the surface .of the crystals.

It appears that all aromatic hydrocarbons'will form -thecomplex with copper fluoroborates. The aromatic Patented Sept. 20, 1960 mesitylene, isodurene, and hexamethylbenzene, ethyl-' benzene and the various polyethylbenzenes, isopropylbenzene, and the Various polyisopropylbenzenes, also the various butyl and pentyl derivatives, such as t-butylbenzene, Z-phenylpentane, etc.; in addition to these, the substituted benzenes containing 2 or more difierent substituents such as ethyltoluene, isopropyltoluene, and ethylxylene; also, the substituents may be unsaturated, for example, styrene, ot-rnethylstyrene, and dimethylstyrene. Examples of the naphthalene hydrocarbons which are suitable are naphthalene, the various methylnaphthalenes, and polymethylnaphthalenes, ethylnaphthalene and the various polyethylnaphthalenes, also the naphthalenes containing propyl, isopropyl, butyl, t-butyl and pentyl substituents. The naphthalenes containing olefinic substituents are suitable, for example ethenyl naphthalene,- propenyl naphthalene, and pentenyl naphthalene. The various indanes are suitable, for example, methyl indanes, ethyl indanes, isopropyl indanes, etc. The various dihydronaphthalenes are suitable, such as the methyl, ethyl, propyl, and butyl substituted dihydronaphthalenes. The various tetrahydronaphthalenes are suitable, such as the methyl, ethyl, propyl, t-butyl and pentyl substituted tetrahydronaphthalenes.

It is preferred to utilize benzene, naphthalene, and the various alkylbenzenes and alkylnaphthalenes whose alkyl groups contain not more than 5 carbon atoms. Examples of these are benzene, ethylbenzene, toluene, meta-xylene, naphthalene and a-methylnaphthalene.

In addition to the aromatic complexes, the copper fluoroborates also form complexes with organo sulfur compounds, such as mercaptans, thioethers, and disulfides. In general, these organo sulfur compounds-copper fluoroborate complexes are much more stable than are the aromatic. hydrocarbon copper fiuoroborate complexes. Itis difficult to recover the aromatic hydrocarbon from these organo sulfur compound complexes. It is possible to separate a mixture of the aromatic hydrocarboncomplex and the sulfur compound complex by decomplexing the aromatic hydrocarbons and separating the decomplexed aromatic hydrocarbons from the copper fluoroborate-organo sulfur compound complex. In view of the difficulty of decomplexing the organo sulfur compounds, it is preferred to operate on a feed mixture of aromatic hydrocarbons and non-aromatic hydrocarbons which is substantially free of organo sulfur compounds.

When a mixture of aromatic hydrocarbons and nonaromatic hydrocarbons, such as paraffins, cycloparaflins, etc. is contacted with copper fluoroborate under essentially anhydrous conditions, a complex of copper fluoroborate and aromatic hydrocarbon is formed. This complex is only slightly soluble in hydrocarbons, particularly saturated hydrocarbons, as to be considered as hydrocarbon insoluble. The hydrocarbon phase which is re. duced in aromatic content with respect to the feed mixture can be separated from the complex, for example, by decantation or filtration where the complex is solid. The complex forms ratherslowly since the fluoroborate is a solid. However, with sufiicient agitation, it is possible to separate essentially completely aromatic hydrocarbons from the feed mixture. When copper fluoroborate is used to contact a feed mixture of aromatic hydrocarbons and nonwaromatic hydrocarbons, it is desirable to use at least about 0.5 mole of fluoroborate per mole of aromatic hydrocarbon in the feed in order to maximize the aromatic separation.

A particularly suitable feed to the separation process of the invention is a petroleum distillate boiling below about700 F. The distillate boiling between about 100 F. and 450 F., i.e., the naphtha range, derived from the product of the catalytic reforming in the presence of hydrogen, of petroleum naphthas is particularly suitable as a source of aromatic hydrocarbons because of its very low sulfur content and olefinic hydrocarbon content. The entire naphtha boiling range material of the catalytic reformate may be used or any one of the narrower boiling range cuts closely boiling about a particular aromatic hydrocarbon, for example, the benzene fraction, the toluene fraction or the C aromatic hydrocarbon fraction.

It has been discovered that the copper fluoroboratearomatic hydrocarbon complex and the copper fluoroborate-organo sulfur compound complex are extremely soluble in anhydrous liquid hydrogen fluoride. The presence of water has an adverse effect on the complex apparently because the BF component reacts to form very stable BF hydrates. The contacting of aromatic hydrocarbons with copper fluoroborate alone or in the presence of liquid HF should be done under essentially anhydrous conditions. should not contain more than about 2% of water. Commercial grade anhydrous hydrofluoric acid which contains on the order of 1 weight percent of Water is particularly suitable for use in the process when utilizing liquid HF medium.

When an agent comprising essentially anhydrous liquid HF and copper fluoroborate dispersed therein or slurried therein is used to separate aromatic hydrocarbons from non-aromatic hydrocarbons, it is desirable to have a feed mixture which is substantially free of olefinic hydrocarbons. This, in order to avoid alkylation of the aromatic hydrocarbons to higher boiling substituted aromatic hydrocarbons. Also, for reasons of economy with respect to the use of the copper fluoroborate and ease in recovery of the copper fluoroborate it is preferred to have a feed mixture which is substantially free of organo sulfur compounds.

Suflicient liquid HP is introduced into the contacting Zone to form a distinct separate acid phase. The copper fluoroborate-aromatic hydrocarbon complex dissolves in the acid phase. The presence of the liquid HF in the contacting zone greatly speeds up the complex formation reaction and reduces correspondingly the necessary time of contacting. The acid phase comprising liquid HF, complex, dissolved hydrocarbons and possibly some unreacted copper fluoroborate is readily separated by gravity settling from the raflinate phase which is of lower aromatic hydrocarbon content than the feed mixture. The contacting may be carried out at a temperature between about 30 C. and about +150 C. Sufficient pressure must be maintained on the system to keep the HF in the liquid state. In general, it has been found that satisfactory results with respect to the extraction of distillates such as catalytic reformates are obtained by operating at ordinary atmospheric temperatures in the range of C. and 35 C., utilizing sufiicient pressure to maintain the HF in the liquid state. Operation at these temperatures is desirable because it decreases the pressure needed and also reduces the side reactions catalyzed by liquid HF.

While aromatic hydrocarbons are removed into the acid phase by the use of even trace amounts of fluoroborate, it is preferred to operate with an amount of fluoroborate approaching the theoretical requirement. In the presence of liquid HF, it appears that the complex containing 2 molecules of aromatic hydrocarbon per molecule of copper fluoroborate is formed almost exclusively. Thus it is preferred to use at least about 0.5 mole of copper fluoroborate per mole of aromatic hydrocarbon to the feed mixture charged to the contacting zone. Amounts appreciably in excess of the approximate theo- In general, the liquid hydrogen fluoride retical requirement may be used when it is desired to remove virtually all of the aromatic hydrocarbon from the feed even though some ditficulty results from the presence of solid copper fluoroborate in the acid phase.

More than the minimum amount of liquid HF needed to form a separate acid phase is used. In general, at least about one-half volume of liquid HF is used per volume of aromatic hydrocarbon in the feed. More than this amount has some beneficial effect in improving the purity of the extract phase and it is preferred to operate with about one volume of liquid HF per volume of total feed.

The acid phase comprising liquid HF and complex is passed to a zone wherein the HF is distilled away from the complex. The removal of the HF may be carried out in such a manner that little or no decomposition of the complex itself results. Or, the temperature in the HF removal zone may be sufliciently high to decomplex some or even all of the copper fluoroborate-aromatic hydrocarbon complex. By controlling the temperature and time of residence of the complex in the HF removal zone, there is recovered in the bottom of this zone a mixture of complex and aromatic hydrocarbon. matic hydrocarbon may be separated from the complex. The complex itself may then be heated to drive off aromatic hydrocarbon in excess of one molecule per molecule of copper fluoroborate, or the entire complex may be decomposed to produce copper fluoride, aromatic hydrocarbon and BF The BF may be recovered and reacted with the copper fluoride immediately prior to utilizing the resultant copper fluoroborate in the contacting zone.

It is preferred to carry out an aromatic recovery opera tion by taking advantage of (1) the solubility of copper fluoroborate-aromatic complex in liquid HF and (2) the reaction of the Cu(BF (Ar) complex with another molecule of aromatic hydrocarbon to form the complex and (3) the ability to remove the second molecule of aromatic hydrocarbon from this complex to regenerate the 1 molecule complex without appreciably decomposing the copper fluoroborate. In this process, the feed mixture is contacted with a liquid agent consisting essentially of (i) liquid HF in an amount at least suflicient to form a distinct separate acid phase and (ii) a complex of copper fluoroborate and an aromatic hydrocarbon, in substantially equimolar amounts, i.e., Cu(BF (Ar) which complex is dissolved in the liquid HF to form a liquid agent solution. The contacting is carried out at conditions of temperature, pressure and freedom from Water as is the liquid HF and copper fluoroborate contacting process. In this operation, at least one mole of Cu(BF (Ar) complex is introduced into the contacting zone per mole of aromatic hydrocarbon in the feed. Preferably the liquid HF is introduced in an amount of at least about one-half volume per volume of aromatic hydrocarbons in the feed and about 1 volume per volume of total feed.

Hydrocarbon raflinate phase containing essentially no aromatic hydrocarbon is readily obtained in a contacting zone providing about 3 theoretical separation stages when the agent contains liquid HF and complex in the preferred amounts. The acid phase, consisting substantially of liquid HF, complex containing 2 molecules of aromatic hydrocarbon per molecule of copper fluoroborate and dissolved hydrocarbons is separated from the raflinate phase. The HF is preferably removed distillatively under conditions to decompose very little of the complex. The complex may then be transferred to another vessel where it is heated under conditions of time, temperature and pressure such that about 1 mole of aromatic hydrocarbon is decomplexed per mole of copper fluoroborate as complex present in the agent. The conditions of time, temperature and pressure used will vary with the particular aromatic hydrocarbon in the feed.

The are-- Whenthe aromatics consist of benzene hydrocarbons and naphthalene hydrocarbons .with alkyl groups containing not more than carbon atoms, such as are found in catalytic reformate boiling below about 450 F., the decomplexing is preferably carried out at a temperature between about 70 C. and 100 C. at a pressure between about mm. Hg and 760 mm. Hg, where the lower pressures correspondto the'lower temperatures; the complex is maintained at these conditions for atime between about '15 minutes and 2 hours; these times being adapted or controlled to remove only one mole of aromatic hydrocarbon from the Cu(BF (A-r) complex. 'It is to be understood that longer times may be usedwithout adverse effect; although, in general, these times will permit essentially complete decomplexing of the one mole of aroto remove essentially all the aromatic hydrocarbons from the feed mixture and recover the aromatic hydrocarbons without significant loss of copper fluoroborate to decomposition products.

The annexed figure, which forms a part of this specification, sets out a preferred illustrative'embodiment of one mode of operation utilizing copper fluoroboratecomplex. his to be understood that the embodiment illustrated is schematic and many items of process equipment are deliberately omitted since these may be added by those skilled in the art.

In this embodiment, the feed is -a catalytic ,reformate boiling between about 150 F. and 370 P. which has been derived fromthe catalytic reforming of a virgin naphtha. Many catalytic reforming processes are noW in commercial use in the petroleum industry, for example, Ultraforming, Catforming, Hydroforming, Houdriforming, and Platforming. This catalytic reformate'feed contains about 50 volume percent of aromatic hydrocarbons.

-In addition to benzene, toluene, xylenes andethylbenzene,

a small amount of C aromatic hydrocarbons is present. This catalytic reformate contains less than 1% of olefinic hydrocarbons and on the order of 0.05 weight percent of sulfur. Feed from source 11 is passed by way of line 12 through drier 13. In drier 13,'the water contained in the feed is removed essentially completely. Drier 13 may consist of a well-known alumina drier followed by chemical drying through lime to remove last traces of water. Any of the well-known-techniquesfor removing dissolved water from hydrocarbons may be used herein. The dried feed is passed from drier 13 by way of line 14 into extractor 16 at a lower point thereof.

Extractor 16 is a vessel adapted for the continuous countercurrent contacting of two immiscible-liquids. Instead of using a countercurrent tower, a number of individual stages providing countercurrent flow may be used. Extractor 16, in this embodiment, provides three theoretical separation stages.

Liquid agent is passed from line 18 into extractor 16 at an upper point thereof. The liquid agent utilized herein consists of hydrogen fluoride and a complex containing about v1 mole of aromatic hydrocarbon per mole of cuprous fluoroborate. The liquid agent containsiliquid HF in an amount of 1 volume per volume of aromatic hydrocarbons in the ifeed, i.e., about one-half volume of HF per volume of total feed from line 14. Also, it contains 1.1 moles of Cu(BF ').(Ar) complex, i.e., about a 10%, excess over the theoretical requirement of '1 mole of complex per mole of aromatic hydrocarhonjn the ,feed. Extractor ,16 ,is ,maintained at substantially anon stant temperature, over its entireheight, of 20 C. and aha-pressure slightly in excess of 15-p-.s.i.a. in order to keep the HP in the liquid state.

From thetop of extractor 16, there is withdrawn by way of 'line 21 a raflinate phase which contains a small amount of occluded agent. The raflinate phase is passed into coalescer 22, wherein the occluded agent is separated. The recovered'agentis withdrawn from coalescer 22 by way of valved line23 and may be recycled to line 18 for reuse in the process or withdrawn from the system by way of valved line 24. Coalescer 22 may be any vessel adapted to facilitate separation of dispersed immiscible liquid from another liquid, for example, coa

lescer 22 may be filed with steel wool. From coalescer 22, the raffinate is pased by Way of line 26 into HF separator 27 which is provided with internal heat exchanger coils 28.

Normally, the extract phase produced in extractor 16 ,contains only a very small amount of non-aromatic hydrocarbons. When itis desired to produce an aromatic vhydrocarbon product which is free of close boiling nonaromatic hydrocarbons, a low boiling paraffin hydrocarbon may be introduced into the bottom of extractor 16 to wash from the extract phase these close boiling nonaromatic hydrocarbons. In this embodiment, isopentane from source 31 ispassed by way of valved line 32 into line 33 and thence into extractor-16. The amount of phase dissolved HF and .isopentane.

wash liquid introduced is dependent upon the effectiveness of extractor 16, butin general, will be betweeen about 0.1 and 0.5 volumes of'isopentane per volume of total hydrocarbons in the extract phase. In this embodiment, 0.25 volume of isopentane per volume of total hydrocarbons in-the extract phase are introduced.

The isopentane introduced into extractor 16 passes out of extractor -16 along with the rafiinate phase. Stripper 27 is operatedto remove overhead from the raffinate Raffinate hydrocarbons containing less than on the order of 1% of aromatic hydrocarbons are withdrawn from the bottom of stripper 27 andpassed to storage not shown by way of line 36.

The'HF-isopentanevapors .are removed from stripper 27 by way of line 37 and are condensed in cooler 38. The total stream may be passed by way of valved line 39 and line 41-to line 33 for reuse'in extractor 16. Or, cooler 38 may be designed to act as a separator and a lower phase of HF withdrawn by way of valved line :42. If it is not desired to recycle the isopentane from line 39, it may be withdrawn from the system by way of valved line 43.

An extract phase consisting of liquid HF,

complex,'CuBF (Ar) complex and dissolved isopentane is withdrawn from extractor 16 and passed by way of line 46 into decomposer 47, which is provided with an internal heater 48. Decomposer 47 is operated at a temperature of about C. at a pressure of about one atmosphere with a holding time of about 2 hours. Under these conditions, HF and some aromatic hydrocarbons and isopentane pass overhead through line 51. These vapors are condensed in cooler 52 and pass by way of line 53 into separator 54. Separator 54 is adapted for the gravity separation of two immiscible liquids. Separator 54 is provided with a vent system 56 whereby any BF which may be formed in 'decomposer 47 may be recaptured, if desired; BF must be introduced in amounts enough to reconver t CuF to Cu-BF in order to avoid buildup of solids in the system. A lower phase of liquid HF is-withdrawn'from separator 54 by way .of'l-ine 57.

From the bottom of decomposer 47 a slurry consisting of aromatic hydrocarbons and Cu(BF (Ar) complex is passed by way of line 61 into washer 62. Washer 62 is a vessel adapted for fluidized contacting of an immiscible liquid-solid with a wash liquid. In this instance, isopentane from line 64 is introduced into Washer 62 by way of distributor -66. The amount of isopentane introduced into Washer 62 is suflicient to dissolve all the decomplexed aromatic hydrocarbon and remove adsorbed aro matic hydrocarbon from the surface of solid complex. The amount of low boiling paraflinic hydrocarbon used in washer 62, in general, is between about 0.25 and 1 volume of low boiling paraflin hydrocarbon such as isopentane per volume of slurry charged to washer 62 by Way of line 61. Herein 0.5 volume of isopentane is introduced by way of line 64 per volume of slurry in line 61. Washer 62 is operated at about ambient temperature and pressure.

There is taken from the top of Washer 62 a liquid stream consisting of isopentane and aromatic hydrocarbons, which stream is passed by way of line 71 into distillation zone 72. The aromatic hydrocarbons from line 58 are introduced into line 71 and pass into distillation zone 72. Distillation zone 72 is shown schematically. There is taken overhead isopentane vapors and these are passed by way of line 73 and line 64 back to washer 62. Makeup isopentane from source 74 is passed by Way of valved line 76 into line 64.

Aromatic hydrocarbon stream consisting of benzene, toluene, C aromatic hydrocarbons and some C aromatic hydrocarbons is withdrawn from zone 72 by Way of line 78 and is passed to further processing for the preparation of essentially pure close boiling aromatic product.

There is withdrawn from washer 62 by way of line 81 a dense slurry of Cu(BF )(Ar) and isopentane. Liquid HF from line 57 is passed by way of line 82 to join the stream from line 81 and to dissolve the complex contained therein. If necessary, some form of mixing device may be introduced at this point, although the extremely high solubility of complex and liquid HF in most instances permits operation with ordinary line mixing. Makeup HF in the form of commercial grade anhydrous hydrofluoric acid is introduced from source 84 by way of line 85 into line 57.

Makeup cuprous fluoroborate is introduced into the system from vessel 86. In this vessel, solid cuprous fluoride from line 87 is reacted with BF from line 88 in the presence of an aromatic hydrocarbon such as benzene, from line 89 and liquid HF from line 91. One mole of ER, is introduced into zone 86 per mole of cuprous fluoride introduced. One mole of benzene is introduced per mole of cuprous fluoride and 6 moles of HF per mole of cuprous fluoride. The liquid HF dissolves the cuprous fluoroborate-benzene complex. The solution is passed by way of valved line 92 into line 83 where it meets the main stream of HF-complex agent. The agent is passed by way of lines 83 and 18 into extractor 16 Instead of using the procedure of zone 86 for the production of cuprous fluoroborate makeup, solid cuprous fluoroborate can be produced in zone 86 by reacting cuprous fluoride and BF and passing the solution into line 92 where it is carried as a dispersed solid in acid present in line 83. Or, instead of using cuprous fluoride, copper metal may be introduced into zone 86 in place of the cuprous fluoride, BF benzene and liquid HF in the same amounts being used as with cuprous fluoride. When using copper metal, provision is made to vent the hydrogen gas produced in the reaction between the copper, HF and BF, to form the cuprous fluoroborate.

It is apparent that numerous modifications of this aromatic separation process may be adapted, based on the teachings herein, and therefore the claimed invention is not to be limited to the explicit teachings set out in this illustrative embodiment.

The results obtainable by the procedures of these inventions are illustrated by the following working ex amples.

EXAMPLE 1 In this example, a polyethylene flask was used as the reaction vessel in order to permit observation of the contents. The. cuprous fluoroborate was prepared in situ by introducing into the flask 81.5 grams of copper powder, 72 grams of commercial grade BF and 657 grams of commercial grade anhydrous hydrofluoric acid, which contained less than 1% of water. In addition to these three reactants, 239 grams of nitration grade benzene Were introduced into the flask. The contents of the flask were agitated by a propeller stirrer for about 8 hours at room temperature 7 of about 25 C. Only one liquid phase was visible in the flask at the end of this time; all the coppermetal and benzene appeared to have been taken up into the acid. A vacuum pump was connected to the flask which aflorded a vacuum of about 10 mm. Hg. The pump operated for three hours at room temperature to remove all of the HF from the flask. At this time, the flask contained a yellowish-white liquid; calculation based on the amount of HF, BF and benzene re covered during the evacuation shows that this liquid was cuprous fluoroborate-(benzene) The contents of the flask were transferred to a metal vessel and heated for 4 hours at atmospheric pressure at a temperature of about C. The materials issuing from the vessel were recovered as well as the contents of the vessel at the end of the decomplexing time. The material in the vessel consisted of a brownish crystalline powder. There was recovered during the decomplexing step two molecules of benzene and one molecule of BF based on copper metal charged to the initial reaction. The solid powder was cuprous fluoride. This work shows that cuprous fluoroborate and benzene, in the presence of a large excess of liquid HF, react to form a complex corresponding to CuBF .2 (benzene), which complex is a yellowish-white liquid at room temperature and pressure.

EXAMPLE 2 In this example, the procedure was carried out in a Hastelloy autoclave provided with a mechanical stirrer. Here also the cuprous fluoroborate was prepared by the reaction of 69 grams of powdered copper metal, 34 grams of ER, and 69 grams of liquid HF in the presence of 26 grams of benzene. The contents of the autoclave were agitated for 4 hours at 25 C. A vacuum pump was used to remove unreacted materials over a period of 2 hours at room temperature. The contents of the autoclave, after the evacuation of liquid HF, etc., corresponded to a complex of cuprous fluoroborate containing 2 molecules of benzene per molecule of cuprous fluoroborate. The contents of the autoclave were raised to a temperature of 70 C. and this temperature maintained for a period of 7 hours while the vacuum pump was used to maintain a vacuum of about 10 mm. Hg on the autoclave. At the completion of this decomplexing treatment at 70 C., the contents of the autoclave corresponded to a complex containing 1 mole of benzene for each mole of cuprous fluoroborate.

The autoclave temperature was then raised to 190 C. and this temperature maintained for 16 hours at atmospheric pressure. At the completion of this time, the autoclave was opened and found to contain cuprous fluoride crystals; one mole of BF and one mole of benzene per mole of cuprous fluoride formed were recovered during the high temperature decomplexing period.

EXAMPLE 3 In this example, cuprous fluoroborate was prepared in an autoclave by the in situ reaction of 155 grams of copper, 180 grams of BF and 420 grams of liquid HF in the presence of 432 grams of nitration grade toluene.

100 C. and the autoclave was vacuum pumped for 20 hours at this temperature. At the end of this time, the stoichiometric amount of cuprous fluoride crystals were recovered from the autoclave and 2 moles of toluene and 1 mole of BF had been distilled over during the final decomplexing stage.

EXAMPLE 4 In this example, the complex was prepared by the reaction of 31 grams of copper, 80 grams of liquid HF, 37 grams of BF and 86 grams of toluene. The autoclave was stirred for 2 hours at 25 C. A vacuum was applied to the autoclave for 2 hours at 25 C. to remove unrcacted materials and also hydrogen gas which is always produced when copper metal is reacted to obtain the cuprous fluoroborate. After the first evacuation, the contents of the autoclave were calculated to be 2 moles of toluene for each mole of cuprous fluoroborate.

The contents of the autoclave were raised to 40 C. and a vacuum maintained on the autoclave, for 24 hours at this temperature. At the end of this time, 1 mole of toluene had been distilled from theautoclave per mole of cuprous fluoroborate therein. The contents of the autoclave then corresponded to 1 mole of toluene per mole of cuprous fluoroborate therein.

The autoclave was then raised to a temperature of 110 C. and maintained there for 2.5 hours while pumping with the vacuum pump. After the evacuation at this higher temperature, 1 had been recovered per mole of copper charged. The autoclave contained a brownish crystalline powder corresponding to the stoichiometric yield of cuprous fluoride.

EXAMPLE 5 In this example, the reaction was carried out in a polyethylene flask. The reactants consisted of copper, 64 grams, HF, 652 grams, BF 124 grams and nitration grade xylene containing about 95% of meta-xylene. The reactants were agitated for 8 hours at room temperature. The unreacted HF along with the hydrogen gas and some BF were permitted to distill from the flask at room temperature. There remained in the. flask a solid residue consisting of white needle-like crystals. The contents of the flask corresponded to 2 molecules of meta-xylene per molecule of cuprous fluoroborate. i

A portion of the solid was transferred to another vessel and heated for 8 hours at 160 C. at atmospheric pressure. At the end of this time, the vessel contained brownish crystals correspondingto stoichiometric yield of cuprous fluoride and 2 moles of meta-xylene, and 1 mole of BF had been recovered per mole of cuprous fluoride recovered.

The crystalline solid complex showed no change in physical appearance on storage in a tightly closed jar. Exposure to some of the crystals to the atmosphere resulted in a change in the color of the surface of the crystal from white to pinkish. This appears to be due to the reaction of the complex with atmospheric moisture since, in the absence of moisture, no visible change occurred in the appearance of the crystals.

EXAMPLE 6 In this example, the complex was formed by the reaction of 80 grams of liquid HF, 4.5 grams of BF and 5.1 grams of solid cuprous fluoride, in the presence of 9.5 grams of toluene. The reactants were stirred for 2 hours at 25 C. All of the toluene passed into the acid solution. i

mole of toluene and 1 mole of BB,

EXAMPLE 7 In this example, nitration grade toluene and cuprous fluoroborate were agitated in an autoclave at 25 C.

The cuprous fluoroborate was prepared by adding cuprous fluoride and B'F in equimolar amounts prior to the introduction of toluene. The behavior of the pressure in the autoclave indicated that the B F reacted with the cuprous fluoride to form a material having a low vapor pressure. The cuprous fluoroborate corresponded to 9.3 grams and the toluene to 30 ml. The toluene was dissolved in 110 ml. of technical grade n-heptane. After stirring for some time, the rafiinate phase was separated from a complex phase. Analysis of the raffinate phase showed that 0.2 moles of toluene had been extracted per mole of cuprous fluoroborate charged to the reaction zone.

EXAMPLES 8 AND 9 In these examples, the etfect of the presence of liquid HF in the contacting zone was investigated. The conditions in these examples were identical with those of Example 7 except for the presence of liquid HF. In Example 8, 4 ml. of liquid HF was added to the autoclave. The acid phase separated from the raflinate phase and the liquid HF distilled away therefrom. The hydrocarbons recovered after complete decomplexing of the toluene contained 95% of toluene. The raffinate phase contained 17% of toluene as compared with 21% of toluene in the feed.

The toluene extracted corresponded to 1.05 moles per mole of cuprous fluoroborate charged. Even this small amount of liquid HF very greatly improved the extraction effectiveness of cuprous fluoroborate as compared with Example 7.

In Example 9, the liquid HF utilized amounted to ml. The raffinate phase from this contacting contained only 9% of toluene. The toluene extracted corresponded to 1.9 moles per mole of cuprous fluoroborate charged.

EXAMPLE 10 In this example, a feed mixture containing 29 volume percent of toluene and the remainder n-heptane was contacted with cuprous fluoroborate and liquid HP at room temperature. The toluene extracted in this example corresponded to 2.0 moles, of toluene per mole of cuprous fluoroborate charged to the autoclave.

EXAMPLE 11 In this example, a feed consistingof 33 volume percent of toluene and the remainder n-heptane was contacted at room temperature with cuprous fluoroborate and liquid H-F. Under these conditions, the raflinate phase separated from the acid phase and was. found to contain only a trace amount of toluene. The hydrocarbons recovered from the extract acid phase contained 92% of toluene and the remainder n-heptane. The toluene extracted corresponded to 2.0 moles per mole of cuprous fluoroborate charged.

EXAMPLE 12 In this example, a feed containing 50% of benzene and the remainder n-heptane was contacted at room temperature with cuprous fluoroborate and liquid HP. The benzene recovered from the extract phase corresponded to 2.6 moles per mole of cuprous fluoroborate charged. This result is high primarily due to the fact that an insufficient amount of cuprous fluoroborate was used to remove essentially all of the benzene. The ratfinate phase contained 28 volume percent of benzene.

For convenience, the details of the Examples 7 through 12 have been set out in the annexed table.

is utilized in an amount of at least about 0.5 mole per mole of aromatic in said feed and said liquid HP is utilized in an amount of at least about 0.5 volumes per volume of aromatic hydrocarbon in said feed.

Table Example 7 8 9 10 11 12 Temperature, 0 25 25 25 25 25 HF l 80 80 350 80 9. 3 9. 3 63 13 Toluene Toluene Toluene Benzene 3 19 26 89 n-Heptane, ml 110 110 70 62 182 35 Aromatic, Vol. Percent- 21 21 21 29 33 50 CuBFn Ar Charged, mole ratio 0. 24 0. 24 0. 37 0.27 0. 51 0.28 Ratllnate:

Aromatics, Vol. Percent. 17 9 16 Tr 28 Extract:

Aromatics, Vol. Percent 95 92 Aromatic Extracted, moles:

OuBFr, moles 0.2 1.05 1.9 2.0 2. 0 2. 6

Thus having described the inventions, what is claimed is:

1. A complex, stable at atmospheric temperature and pressure, consisting essentially of Cu(BF. (Ar) where x is 1, y is 1 and Ar is an aromatic hydrocarbon from the class consisting of benzene and toluene.

2. CuBF .1 (toluene).

3. A separation process comprising contacting a feed liquid mixture comprising aromatic hydrocarbons and non-aromatic hydrocarbons, under essentially anhydrous conditions, with copper fluoroborate, thereby forming a hydrocarbon-insoluble complex of copper fluoroborate and aromatic hydrocarbon and separating said complex from a liquid hydrocarbon phase having a lower aromatic content than said feed, said copper fluoroborate being added in an amount at least suificient to produce an amount of said complex in excess of the solubility thereof in said liquid hydrocarbon phase at the temperature of contacting.

4. The process of claim 3 wherein said fluoroborate is cuprous fluoroborate.

5. The process of claim 3 wherein said fluoroborate is utilized in an amount of at least about 0.5 mole per mole of aromatic hydrocarbon in said feed.

6. The process of claim 3 wherein said feed is a distillate boiling below about 700 F.

7. The process of claim 6 wherein said distillate is a catalytic reformate boiling between about 100 F. and 450 F.

8. A separation process which comprises contacting, under essentially anhydrous conditions, a feed mixture comprising aromatic hydrocarbons and saturated nonaromatic hydrocarbons, in the substantial absence of olefinic hydrocarbons, with a treating agent comprising copper fluoroborate and liquid HP, in an amount suflicient to form a distinct separate acid phase, at a temperature between about -30 C. and +l50 C. at a pressure at least suflicient to keep the HP in the liquid state, separating an acid phase comprising liquid HF and copper fluoroborate-aromatic complex from a raflinate phase containing less aromatic hydrocarbons than said feed.

9. The process of claim 8 wherein said feed is substantially free of organo sulfur compounds.

10. The process of claim 8 wherein said feed is a distillate boiling below about 700 F.

11. The process of claim 8 wherein said feed is a catalytic reformate boiling within the range of about 100 F. to 450 F.

12. The process of claim 8 wherein said fluoroborate 13. An aromatic hydrocarbon recovery process comprising (a) contacting, under essentially anhydrous conditions, a feed mixture of aromatic hydrocarbons and saturated non-aromatic hydrocarbons, in the substantial absence of organo sulfur compounds, with a liquid agent consisting essentially of (i) liquid HF, in an amount at least sufficient to form a distinct separate acid phase in the contacting zone, and (ii) a complex of copper fluoro borate and an aromatic hydrocarbon, in substantially equimolar amounts, said complex being dissolved in said liquid HF, at a temperature between about 30 C. and +150 C. at a pressure at least suflicient to keep the HF in the liquid state, (b) separating a rai'finate phase containing less aromatic hydrocarbon than is present in said feed from an acid phase comprising HF and copper fluoroborate complex containing substantially two moles of aromatic hydrocarbon and one mole of copper fluoroborate, (c) distilling HP from said acid phase to recover the complex therefrom, (d) heating the complex recovered from said acid phase under conditions of temperature, pressure and time such that one mole of aromatic hydrocarbon is decomplexed and (e) separating complex containing substantially one mole of aromatic hydrocarbon per mole of copper fluoroborate from said decomplexed aromatic hydrocarbon.

14. The process of claim 13 wherein the HF distilled ofl? in step c is utilized to dissolve the complex separated in step e and the solution is recycled to the contacting zone of step a.

15. The process of claim 13 wherein the agent consists essentially of liquid HF in an amount of at least about one-half volume per volume of aromatic hydrocarbons in said feed and complex in an amount of at ieasit one mole per mole of aromatic hydrocarbon in said 16. The process of claim 13 wherein the temperature of contacting is between about 10 C. and 35 C.

17. The process of claim 13 wherein said aromatic hydrocarbon is selected from the class consisting of benzene, naphthalene, alkylbenzene and alkylnaphthalene, said alkyl groups containing not more than 5 carbon atoms.

18. The process of claim 13 wherein said feed is a catalytic reformate boiling within the range of F. and 450 F.

19. The process of claim 18 wherein the complex recovered from said acid phase is maintained at a temperature between about 70 C. and 100 C. at a pressure between about 10 mm. Hg and 760 mm. Hg, the lower pressures corresponding to the lower temperatures, for a time between about 15 minutes and 2 hours, the time being adapted to remove only one mole of aromatic from the complex recovered from said acid phase.

20. The process of claim 13 wherein said fluoroboratc is cuprous fluoroborate.

21. The process of claim 13 wherein the complex of step e is washed with a low boiling paraflinic hydrocarbon to remove decomplexed aromatic hydrocarbons.

22. CuBF .1(benzene).

14 References Cited in the file of this patent UNITED STATES PATENTS 2,713,552 Lien et a1 July 19, 1955 OTHER REFERENCES Warf: I. Am. Chem. Soc., vol. 74, pages 3702-4 (1952). 

13. AN AROMATIC HYDROCARBON RECOVERY PROCESS COMPRISING (A) CONTACTING, UNDER ESSENTIALLY ANHYDROUS CONDITIONS, A FEED MIXTURE OF AROMATIC HYDROCARBONS AND SATURATED NON-AROMATIC HYDROCARBONS, IN THE SUBSTANTIAL ABSENCE OF ORGANO SULFUR COMPOUNDS, WITH A LIQUID AGENT CONSISTING ESSENTIALLY OF (I) LIQUID HF, IN AN AMOUNT AT LEAST SUFFICIENT TO FORM A DISTINCT SEPARATE ACID PHASE IN THE CONTACTING ZONE, AND (II) A COMPLEX OF COPPER FLUOROBORATE AND AN AROMATIC HYDROCARBON, IN SUBSTANTIALLY EQUIMOLAR AMOUNTS, SAID COMPLEX BEING DISSOLVED IN SAID LIQUID HF, AT A TEMPERATURE BETWEEN ABOUT - 30*C. AND +150*C. AT A PRESSURE AT LEAST SUFFICIENT TO KEEP THE HF IN LIQUID STATE, (B) SEPARATING A RAFFINATE PHASE CONTAINIG LESS AROMATIC HYDROCARBON THAN IS PRESENT IN SAID FEEDC FROM AN ACID PHASE COMPRISING HF AND COPPER FLUOROBORATE COMPLEX CONTAINING SUBSTANIALLY TWO MOLES OF AROMATIC HYDROCARBON AND ONE MOLE OF COPPER FLUOROBORATE, (C) DISTILLING HF FROM SAID ACID PHASE TO RECOVER THE COMPLEX THEREFROM, (D) HEATING THE COMPLEX RECOVERED FROM SAID ACID PHASE UNDER CONDITIONS OF TEMPERATURE, PRESSURE AND TIME SUCH THAT ONE MOLE OF AROMATIC HYDROCARBON IS DECOMPLEXED AND (E) SEPARATING COMPLEX CONTAINING SUBSTANTIALLY ONE MOLE OF AROMATIC HYDROCARBON PER MOL OF COPPER FLUOROBORATE FROM SAID DECOMPLEXED AROMATIC HYDROCARBON. 